It is just over a quarter of a century since Harry Jerison published the first edition of his seminal work, Evolution of the Brain and Intelligence (1973). At the time and in the decades since then, we see it as one of the most significant paleo-neurobiological landmarks which heralded the final quarter of the twentieth century. As we enter the twenty-first century, that work remains ineluctably a signpost for the coming era. It is pleasurable indeed to offer homage to Dr Jerison – who was born one day before me in what seems to have been something of an annus mirabilis, 1925 – and to offer him my thanks for his inspiration and his friendship.

When we consider the ancient hominins, one is struck by the fact of how few have yielded good natural endocranial casts (endocasts).